/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.protocol.influxdb.function.selector;

import org.apache.iotdb.db.mpp.plan.expression.Expression;
import org.apache.iotdb.db.protocol.influxdb.constant.InfluxSqlConstant;
import org.apache.iotdb.db.protocol.influxdb.function.InfluxFunctionValue;

import java.util.List;

public class InfluxMaxFunction extends InfluxSelector {
    private Double doubleValue = Double.MIN_VALUE;
    private String stringValue = null;
    private boolean isNumber = false;
    private boolean isString = false;

    private Double maxValue = null;

    public InfluxMaxFunction(List<Expression> expressionList) {
        super(expressionList);
    }

    @Override
    public InfluxFunctionValue calculateBruteForce() {
        if (!isString && !isNumber) {
            return new InfluxFunctionValue(null, null);
        } else if (isString) {
            return new InfluxFunctionValue(stringValue, this.getTimestamp());
        } else {
            return new InfluxFunctionValue(doubleValue, this.getTimestamp());
        }
    }

    @Override
    public InfluxFunctionValue calculateByIoTDBFunc() {
        return new InfluxFunctionValue(maxValue, maxValue == null ? null : 0L);
    }

    @Override
    public void updateValueIoTDBFunc(InfluxFunctionValue... functionValues) {
        if (functionValues[0].getValue() instanceof Number) {
            double tmpValue = ((Number) functionValues[0].getValue()).doubleValue();
            if (maxValue == null) {
                maxValue = tmpValue;
            } else if (tmpValue > maxValue) {
                maxValue = tmpValue;
            }
        }
    }

    @Override
    public String getFunctionName() {
        return InfluxSqlConstant.MAX;
    }

    @Override
    public void updateValueAndRelateValues(
            InfluxFunctionValue functionValue, List<Object> relatedValues) {
        Object value = functionValue.getValue();
        Long timestamp = functionValue.getTimestamp();
        if (value instanceof Number) {
            if (!isNumber) {
                isNumber = true;
            }
            double tmpValue = ((Number) value).doubleValue();
            if (tmpValue >= this.doubleValue) {
                doubleValue = tmpValue;
                this.setTimestamp(timestamp);
                this.setRelatedValues(relatedValues);
            }
        } else if (value instanceof String) {
            String tmpValue = (String) value;
            if (!isString) {
                isString = true;
                stringValue = tmpValue;
                this.setTimestamp(timestamp);
                this.setRelatedValues(relatedValues);
            } else if (tmpValue.compareTo(this.stringValue) >= 0) {
                stringValue = tmpValue;
                this.setTimestamp(timestamp);
                this.setRelatedValues(relatedValues);
            }
        }
    }
}
